Code No. P0489: EGR Valve Position Sensor Circuit Low Input




OPERATION




FUNCTION




TROUBLE JUDGMENT


Check Conditions
Judgment Criterion

FAIL-SAFE AND BACKUP FUNCTION




PROBABLE CAUSES




DIAGNOSIS PROCEDURE


STEP 1. M.U.T.-III data list



  • Refer to Data List Reference Table .

  1. Item 16: EGR valve position sensor

Q. Is the check result normal?

Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).
Go to Step 2.

STEP 2. Perform voltage measurement at EGR valve assembly connector.



  • Use special tool test harness(MB991658) to connect connector and measure at pick-up harness.
  • Ignition switch: ON
  • Voltage between terminal engine-ECU EGR5 line and body earth.
OK: 4.9 - 5.1 V

Q. Is the check result normal?

Go to Step 6.
Go to Step 3.

STEP 3. Perform voltage measurement at engine-ECU connector.



  • Disconnect engine-ECU harness, and connect special tool power plant ECU check harness (MB992291) to measure at connector for inspection.
  • Ignition switch: ON
  • Voltage between terminal EGR5 and body earth.
OK: 4.9 - 5.1 V

Q. Is the check result normal?


    Repair or replace the connector, or check and repair harness between EGR valve assembly connector terminal and engine-ECU connector terminal EGR5.

    • Check power supply line for open circuit and damage.
Go to Step 4.

STEP 4. Check harness between EGR valve assembly connector terminal and engine-ECU connector terminal EGR5.



  • Check power supply line for short circuit.

Q. Is the check result normal?

Go to Step 5.
Repair or replace the connector, or repair the damaged harness wire.

STEP 5. M.U.T.-III data list



  • Refer to Data List Reference Table .

  1. Item 16: EGR valve position sensor

Q. Is the check result normal?

Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).
Replace the engine-ECU.

STEP 6. Perform resistance measurement at EGR valve assembly connector.



  • Disconnect connector, and measure at harness side.
  • Ignition switch: ON
  • Resistance between terminal engine-ECU EGRE line and body earth.
OK: Continuity (2 Ω or less)

Q. Is the check result normal?

Go to Step 8.
Go to Step 7.

STEP 7. Check harness between EGR valve assembly connector terminal and engine-ECU connector terminal EGRE.



  • Check earthing line for damage.

Q. Is the check result normal?

Go to Step 5.
Repair or replace the connector, or repair the damaged harness wire.

STEP 8. Perform voltage measurement at EGR valve assembly connector.



  • Use special tool test harness (MB991658) to connect connector and measure at pick-up harness.
  • Engine: Idling (after warming up)
  • Voltage between terminal engine-ECU EGRP line and body earth.
OK: 2.0 V or higher

Q. Is the check result normal?

Go to Step 10.
Go to Step 9.

STEP 9. Check harness between EGR valve assembly connector terminal and engine-ECU connector terminal EGRP.



  • Check output line for short circuit.

Q. Is the check result normal?

Replace the EGR valve assembly.
Repair or replace the connector, or repair the damaged harness wire.

STEP 10. Perform voltage measurement at engine-ECU connector.



  • Disconnect engine-ECU harness, and connect special tool power plant ECU check harness (MB992291) to measure at connector for inspection.
  • Engine: Idling (after warming up)
  • Voltage between terminal EGRP and body earth.
OK: 2.0 V or higher

Q. Is the check result normal?

Go to Step 5.

    Repair or replace the connector, or check and repair check harness between EGR valve assembly connector terminal and engine-ECU connector terminal EGRP.

    • Check output line for open circuit and damage.